SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e4605daf7a612f3a04c36f050f5c21d6fce511b927cd36dc25036291e699d2e' 
  AND token = 'TjbuyZjb1IoG7jIT573+s8hgp/8+gXlXjQHpwknO5lU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}