SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c44dfad5edf9a86a25d15fdf21b20ee2be2611360f9af94e49ac2e94ab71f37' 
  AND token = 'uRQ5pql0D1FAF2x/sqTuoE43CvI8PX9Fbk3DNMVtWTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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