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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2df7579b13e59f04b21b9cb1fae73515ad7d38a29c079e3feb5b1c7e1d7ad1f' 
  AND token = 'pcGQY3kq3TIrpGimEaye7MS2Keq0kATnNtnNOAj5gDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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