SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2b314d04e6b4e4ebab6ea6d0ce12bfde222e1b0fc21a9f6297bd918d845efc5' 
  AND token = 'iui7favbOWDRKphCbeRPv8+UQWFfOHf38GduK1IH5Ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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