SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4911c36291e7c796041dd77bf7a89b53654bedb04f97b53d3c5e65bf7bc173f' 
  AND token = 'fMkl8aNogcxhR27TUwf2+oYDwsqOeaXsPLErddIqOOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}