SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c547e4271ae6a3908fae4c303dccc29e3cddbf0762fad5f61266a4dd828529' 
  AND token = 'AlDqRzp4zXhnAC9TPRbDI/GjDOQPoR5Q/OmElT+Y0MU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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