SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ffd7ce9902b5cb603d2b7a80270d388cffc313a174ebe29ed615db1fbc1c6e1' 
  AND token = 'UL18cDeGAaWJyDwm2JO0fgHTf224KZEpVcISWDZvwD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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