SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '573d48325f1a712fc9d5301d530133be72b8e9f2560381227822586f06c5e88c' 
  AND token = 'isHgKo+lrZ2ho/oyA8sNwzkJlZz04M+HEfpSj6EMcW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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