SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24d7bd009d74a25912b6049138f9a3571b665ad3bd0487e77fff8a9404b263c7' 
  AND token = 'gSOJbYU5ecp3fVQFwPq9Hqgw6x+5Sd5dxRtrcCKmE3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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