SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '873c2684c6256d2b428e0a2fe112ff0b43af41e32a69f016019ec1b4eba87f52' 
  AND token = '5CtxzFGBM8ZBPx7m2Po+LFUqA/KfJX5XU0ea1LI5xGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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