SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85c8f97acbe357eb9e875f410ef5d02e387d1cb301a84830091b56f3705547fc' 
  AND token = 'qRHDuF/yePgdOiMp3VJNvoyrgTVSR0zw+2pquW0ml5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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