SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7c7c157a943bd377e0502d5facec76f370564d5e991345329451230cb058100' 
  AND token = '25C+XoPCxvtS8Wll8f24ZglUP2PcBklcXC8X268gSxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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