SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6288569f5b6f4cc6fb45e09ae573163a6e23a036c1a7df270d3ba26575e037e1' 
  AND token = '/yprOAeRsUxmfx8058IA+8ki2RCehgCpUe/IST5/vSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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