SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bad817891e67340284381727194a3457aee185153491c959b523c2b0a1a4946c' 
  AND token = 'gHpYT8djv66GulWW84QsZ+RbrmF7FIVV4168PQMAngI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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