SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db0cb307dd2305e7bfa62abd156a195b6c2c7029bec6ad9de7089ddf56221f14' 
  AND token = 'pE26SfRVWTYi4byjvE5JZgw/08rUGE5J3MGKykdxadI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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