SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c313ab6fe4a9b84b1cc1c01ef20b7d3fe1e1989cf489d5a21b75fcd23e8abaed' 
  AND token = 'HuIMdSrRdH6MYLBgL0LFrCcWZS81Uka8M9qwO+oWsSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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