SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f016bdd5235490302dca6d5de56f009aff839a824d49e17a840aef6af116b29' 
  AND token = 'l0BeLVAnoNApOAh/H2/KupEWi1LkgkOG5PVuL9hgwQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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