SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea596f98e778e59ad274e48e1509ac54699848015ef017307c31db459fc6c71f' 
  AND token = 'vLQqMNU6OCjObn7mKwgae80GqDRDUkOZjfRaaRcOUqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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