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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef3fcd0a53cf4243cced29c487fb0dd60353dcc6573307eeabc697e4d01bc5cb' 
  AND token = 'gYv0bM7Sv7fqSOzGLp/DJrE2Pk2xX0b/JeV0BEi7yI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}