SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a63da2bc95e989e97177442f9e80ccf29e0e759c4b91695a5f51b8a1d129d28' 
  AND token = 'b8osnDrKNOr2nmQSHYX/XRVxzJ1sihT26GBD6luCvRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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