SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6d0a4d943ca7c3279dd6681f742206b1dcc2b2986ffb553d5cd9e830585038d' 
  AND token = 'HPVt46qzgqKvSzkl41cBLu/N+wFsfcTPcfRcZUzkfnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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