SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f2c3655004fd237b51ff07b250a7ce51a93eed8b638e2a40c9fb31ff24d60d89' 
  AND token = 'teNWQGqKTDMaE1Pue429QDZEgAkVnhkTr3rCu/IoLa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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