SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '936da4ef0405ece72e5bbb6ec6e5778bd436ebaeab000b0d64941b51bdc8286c' 
  AND token = 'Y4HAo2P66xgQ20I59SH7Wnhx9qx/+DDbeTN28PRlnAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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