SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ee49f908894cb5a34915baf31cac60142f42a2b40ce4ac71248976ab02eef99' 
  AND token = '6r4ljS3QPOZw8ucvb1GM3T+XeI+v8U9FE0q8s42BcaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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