SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73228e46e3fc5647c53882a67e16426caf9c2d5ed0a7ca1fe784063718a5f2d' 
  AND token = 'Ccw2VhZqEPk+Vff+5gs672+bBuCh9U0OylzH/MV0EOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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