SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beaee8ed43dbdfae2e1b91869e2e706b5297c5c66221349391c757e389001a0b' 
  AND token = 'Cb5ffSeZMXzN7+HllgJ+kFM2QVPfE/SwmKHbKsDr4qM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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