SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8f94263b5b902a1028f02606cbf97fa6492245e94017db73540f6525dd169d37' 
  AND token = '6Myq9I24j9S0/Xrdqy9/sxMe+OXq9z7gpnZdNqREEw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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