SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '197cf5909dd2a0dde3419ce27d827079afee182c280bed0a4cc3761fa54540c8' 
  AND token = 'j7CRqvJICDFMQU/MV1Ut/YfED6G6TfLDuRZGLxfMCxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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