SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63ea12b7e868bb58ab6f0f3c1c4a0fab1a88c15ee2046829e8ca37b7fc2bda45' 
  AND token = 'k3y2EUFZ21mecRd3IyzdpbhfUpVQsN0Re20qWauWzTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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