SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78eac5afe245a19b368dfcb0387003ab0aac23fb6bd2848feda0e50786aeb094' 
  AND token = 'GmK8Z/02StLHeKOkRoKmuKN9cWk1DxiBK5YDHToPzM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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