SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebee4a38c40b1aa070189461644089c7aff98227869fd7667431f02b2d73d2fa' 
  AND token = 'pWPRW2dG+yRLjrnxrG9xRantc61qC7lOFNfHCb3rDdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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