SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '264a3e02b4617acf8cbf379295879ea245622047b0c33b509318653432f7d29a' 
  AND token = '/DEGLa1qKo3l/fwCf5UtUU79F917AGS7YVC5uCEGHgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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