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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ebd5242e2b01da687e85c5d60dbd5f27ee490ffc0268f68bf39f8719b76a50' 
  AND token = 'MMpHdaFQY8gge1a4LvLRqjSPhkDY+0qG+jhlENkM6Yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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