SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8fd9dfae4cebb3aad3184cb2fc357fff9e8d6c12afd5d772171cb053b3d70d4' 
  AND token = 'vmhnEUy8HYk5y7uAu9yibeaw0U0Af0F1OKCHx+QItZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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