SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7ea1085a592138f69b081ade1aa9b357d2f083d5a3d4a242c2963a6cae460b5' 
  AND token = '/tkZH/6kZLOKDk9nwin1XbDxeMVMRJ91jY+A1WR5CcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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