SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a583d6770ae29f86089b7758deb626cc4a43e9747a04ed1868ad28956fbb5670' 
  AND token = 'mSOFyR9ifbmFy+/nrmTqdXq2lps9mM+b9iGmAr+OT7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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