SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cefaf5c871f9f6b938d37142ebf03f454df3078d5a967722d0dc78214acf3496' 
  AND token = '9U/xrGMkDri/qLaUEpcmW0lpeHkU9TfFJXdmJhOHiNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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