SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe68fbf62318f7782f05b3911d7cf13355b8c76e7d9ce4388d0dcdc982119bc9' 
  AND token = 'DJIdLP0KM0kOJLTr7sFK/5XGibRAXNteZSPW77bm3pA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}