SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ddfee5441c651f9bd91fcbffc836cc975a83092893c68eda2f78f49404bc81e' 
  AND token = 'BnlLbbNyrujZ0YhJLrzYpwacyLTiGMXRmbz4qpxqqTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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