SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdbbb52fb9afbd18e687850ab71e5014ae5d12b3b4a651a07d257d43adf1cf39' 
  AND token = 'KKLiJDrISTEs8upiI0KO9X7xjbCB1zU2PzaAGl2a+jY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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