SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '470e32644277d38f5c160067a7aacf674755fab446924995908c751344d379cd' 
  AND token = 'd5KqIg0SOIRrJ3iYQ3VWr6fPM9zsp2eDuiYhbrqYwZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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