SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a73460a6e7f81816f1c508de4146546749787355e72f05ff24835977c301c8cc' 
  AND token = 'fjGCO9IuObNXhHho2tFtk+j7rQ3QscBsJmJp5mOG3QY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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