SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bdc4bcfadb6476217d1946cd2e146a871c569b5e055f54131f2d70fdc31092d' 
  AND token = 'd347guHSLt/fgMEDJAEF8pmHA3MO+7RAbYxrka6g0aQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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