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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de09e5210cfba3528b9cf8b7ff1b6d833e8837cf72c6f7def7fa0f0501bea9f7' 
  AND token = 'T9ot5ppMEkEcfTsp8aJ+i9G6RwbXrO+/APymR79HmDI=' 
  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"
    }
  }
}