SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67fde863729e77236f28308c0607c462b48525b4540a44e538207a44c6d1c12e' 
  AND token = 'AQKcmN4AHCqRPLeTHfBNgkEj6g5dr3nezDfGefnREfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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