SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af640477732e91a109d8904ffef3b591a3fe34ff5db27473c87a728633b3abc1' 
  AND token = '2norK2HTCAaQxBXNRGK1guwGzi1Umj9Ku/+q5L9fe68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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