SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b73aed2f9be77cc967a63e1ed3134d7196c3059f54ff86ba0f10c9da3eefab1' 
  AND token = '0bT23OrAK+3q3ve6i1pb61PugFbTQuMbWEKYakPyXlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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