SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1f068cff228c0a98e750e983bb1be85b8646da36f2db6d736156600e3f1bf11' 
  AND token = 'oQ7sV0QDp9XWEC5EbFokJGUCpwVe5ZHhRN6PRZFMVVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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