SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cffb78152680d36fdcb0325148909338ed309ccd3b1ffd1a48ec3574efba82b' 
  AND token = 'IDWgT+Amib0byjC5eI25bKMw9Dept/J1aHefkmeVhIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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