SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e1c9c636423be4b52efb9e3ebd6c8964cb96d93856d8eb91fc52153484afb80' 
  AND token = 'Lzw8Gadkm6wZgVxBqTh5sBk53SCZMHizGvxy+/hyuQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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