SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd45b2e091bb6896ce911f71d62104b35bd965c12909f2f6ae70584b7f502426' 
  AND token = '5lR4/ZeWxowHo1OhT8enuXgJi6if5upkIxdteaAw0fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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