SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd428bb289348f295479da58ed2b90e4d185c2e9df42601d84fbb78e1b3c956f5' 
  AND token = 'Zgb4XbKBu7Rm+Y3x8jukIqUzY2/RqUSwiHAvEFdfcro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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