SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '12125edb8b992fc97799de33c0f59a9666646e95be07e4ae49483647e094299b' 
  AND token = 'FSXor+xvwHKA+3p2wKRhbhZdYm/J75wIfvM2Ri6FcQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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