SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce8a98e6223546f9cec518e8f84917de6367f246c48a01a4fddd1c584def1ff' 
  AND token = 'rXwWN+dk6kqol/yUhN+MtVCLap9KwcvE37ofw7rSfjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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