SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e17d8be8c9896eabba98e4f4a6bf97bf732c8ae2cfb4d3de0330a9adc85b6d5' 
  AND token = 'n7zDiG9/SqdnbtVMzj+fMAbKA2TmDERZp5oqzfOxUj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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