SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dbd51c626bdd1f70022913cf7bf72cad311c028ec5f28b04e00b6ef84e19b53' 
  AND token = 'TWqw98EsvwArZoZ89pnBVOd3OUPrzJywq3zPLqXpGUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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