SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7f68e1900b8bebb5cb08b47a2de1a5d37fac056146e9f51b8b4b532467b2dba' 
  AND token = 'bDeywOibFj0L0hZQs4XBHMvjxxML0TY1AKnujw3L61k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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