SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3824d6d6b88bc49078ecabc8b1e83abf962963dd0bdcea08733d4e41b13472d8' 
  AND token = 'Z+dvggTw05WE1KAUMjGQqvhcNAXk/aqZH6rNBvwVUSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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