SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5022e30cfb9aa25ac70dcfdf433c3ad6a9c189796f165142cde68a7d8b9f2c3' 
  AND token = 'VtlQLNf5qd9KDRh+1UvaVfUyt4S2wj5ml2bghX1IntY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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