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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a319f8a4405e3e3cc2d5eebee9eef1f57530d0d7512cf7aba85cad22b9ca102d' 
  AND token = 'PEPA/+8B7bSC2JRhiOvabJad3okBbzxTMSwx2Kpiaqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}