SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef9ff34ac7678dcc7e867e2003e96f610d8bb34f3515f035fe1bd0bdb8e2f085' 
  AND token = '29/BEwp55UmfCTNGwSgvcKurNAQzUFGbVlaWnu/dW0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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