SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd09aead8024d65f2f5d6e73920f8b4b50f42d27646edec50ffc9e622e949011' 
  AND token = 'z1eBC+Mz7UwdcoxoSR9nwSWlBataZV+hIcGOFmyk2IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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