SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c381c6e34023cee7433b4b1207f9eb0a35148f12279da4fe95f5180779f3110' 
  AND token = '6DnC6qQ4uPFx7Tr143Cg3WvGXe4i1ZFPZoL82vw6mjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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