SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa79704751d9cdbedcefe0f3c6252cb1936b6a7b56375b693b09e9dd2d476351' 
  AND token = 'j1IE540nayxPZxs8vfE6FCDWFUg09ghA+gh+bKLz70o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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