SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453d870d3dd91362c318a26f1272eb6191933ae1aa19cec1691bda011257e418' 
  AND token = 'h7iJ0zdUvqVgJ0JWHzDaKok7qO5eDDghrZmktB6zIg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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