SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50d7eae057b43d8ea567215a14a261ec54ca6db01f0d28073854479ee89b4fad' 
  AND token = 'NI2B0evjHVeSaX8sQmq82hXf+Hqd87r2WPmQZGyEbxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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