SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '583b52de1439e654f19039b70dac2cc6e1624711b5b6adb551f2eff7894ef70c' 
  AND token = 'NSRmmrpDYdWqcXsYpZNCKs7xzGXJL4WFapGw+CA9OB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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