SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f6cca7294ac740d89c59cfbdfdc8464586010328c634ad327ff68e725e11feb' 
  AND token = '7lnqrOo7cUrK6gt5Ykr+oVidWdxTKk8LPXlyP5rZN9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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