SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d78f3cb390dd755d874884446b0214a35855143129ace9b7e12edf0bd51892a' 
  AND token = 'HFGSxqUIl1N+Y0Tg4zjOzGDz4fLZRdxQ/f08SnK+pQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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