SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c776e6ca7f124ecb1f3dd8ac131d4823234bbcbe57280675571c6a563c282e47' 
  AND token = 'XBIE7+suJ42iMxmZ7EkjOcMds9+RnIiwFhZpmvID6rY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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