SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4012f48f8b11daa1b40adef4b80307b6a714d49b6ec6cbd15a7b9d6ff8dd9eab' 
  AND token = '8kDo5gWBLE8Yh4bH5dpsKmxGqMwxpIAXGBhyJV+Q8Dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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