SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c53e37e08798d205adbcb336c5e609525bf6c728cd571d5934aefc1d2dff36b' 
  AND token = 'vVMwEn7qXKckGSjFd+3Uk+Ay82V/gh8qx1Poiw9DCAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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