SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8b8e455558a3321ad177890b2136cd9d84d884a565add9047bc3261b34960cc' 
  AND token = 'J8Yj2rIbtsfB/7ZIF1tWpPE5OmJ/VH3dgQ3wfgJ9xX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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