SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cf54191301f5e07d74904c65394208cd4241e01a87fdc34e50299928dd92ad4' 
  AND token = 'dV33iSt05GJRVN72xxnJtvalfvsc+sZj8vC0KzAM5qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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