SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd448dc7f70d5ca9e5748184e140cefab98d1fcda63fd44c5d86e7650be0d01d7' 
  AND token = 'kV6I/PCCNwKtLj2R+XIWejAdRqBUdyvpqwB37/gGRvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}