SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8e4459b007a3802f11f735146321d7824995af3d71224de99d683a60d13561' 
  AND token = 'hnOfE6LVLiJ/ZGdlTIeHcBvBY3R9npFhx/6ODwF0Nl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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