SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b900096d9f11e598ff210df3958b430158f3bd90a398e17b540858278077ac19' 
  AND token = '2KzlafwEyz5o8fLNaxCOCQRYc9Xsyl/yh4CZNSKpkkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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