SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '694dc68fd3a34f358dca18266c7035198581381a16e85cc2f73470c2096e7ad8' 
  AND token = 'cIyYlBt4lMR+WRbtZIHQ3oi7FlgkbEBkueZkBUg5Pmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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