SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a5c5834c1d83587f64e0405d4a081aceb4f429d521ae48a2867cda5d223f92a' 
  AND token = 'YrM35OTcYZoX7KSSqw2Qfr3Q8eHEIs66rIEKCm8vc8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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