SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '417d2c10122dccb6f12784804407fa206df4b734e94505d03a355d93146b0dc4' 
  AND token = '0QCjSpgAIJikgtCq8da+qH4xPMh0V2gwzB7KF2LcJdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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