SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6db5cabcd342cc9417bfc4447463f9a2f19310509922a71428333843428e9806' 
  AND token = 'AFfnt9Mly21TC8aQUKUM25LgdNWlswHReMHuG/FDeHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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