SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78fb7a9b8b2597bd68837b18535aef88af018d5e7959bac554fb434f7c66211' 
  AND token = 'jwXMGIaYHJJEmRWRqmL4hwkBtgdn1VTUg6ybMK8oBRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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