SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b85f5d78488af1556be20a5b71a29d9488b89687a9e8ac48ca81470ceffd6eb' 
  AND token = 'QOf+ulE1JM+lDjR6SzeMPJhCqwpaYsP4ro3PMJ8SQdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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